[lug] Resolved: Re: Dropped packet question

[Chip Atkinson]

Yeah, there was some other really weird ping stuff going on too.  The
cable "modem" had some diagnostic tools, including ping.  ping 75.75.75.75
(the name server) showed ping responses from *my* IPs, 173.x.x.x! 


On Mon, 30 Sep 2013, Quentin Hartman wrote:

> ICMP-based ping can indeed give weird results when used by itself. I've
> given up using as a diagnostic tool beyond "A can talk to B". I've found
> that mtr and lft are far far more useful, but they are usually not part of
> default installs.
> 
> QH
> 
> 
> On Mon, Sep 30, 2013 at 12:00 PM, Chip Atkinson <chip at pupman.com> wrote:
> 
> > Hi everyone,
> >
> > Thanks for your help last week.  I spent a few hours working on the
> > problem yesterday and believe that it's now fixed.  The most likely cause
> > was a cable.  After replacing that particular one, the problems started
> > drying up.  Granted it could have been something else and part of me wants
> > to put the suspect cable back in, but I'm torn between moving on with my
> > life and validating my suspicion.
> >
> > One red herring worth mentioning was that I was using ping as a diagnostic
> > tool against the comcast name servers.  Turns out that DNS queries went
> > quite quickly whereas pings were sometimes getting dropped.  It makes
> > sense that DNS queries would get the best QoS ratings(?).  I ended up
> > using dig which reports query times and they were all in the few
> > millisecond ranges.
> >
> > Thanks again.
> >
> > Chip
> >
> > On Fri, 27 Sep 2013, Chip Atkinson wrote:
> >
> > > Hmmmm... yeah, this would fit the behavior of some packets getting
> > > through, others not.  Right now I'm not in front of the machine and only
> > > one interface is plugged in (and the management interface is unplugged
> > > too), so if I make a mistake I'll cut myself off entirely.
> > >
> > > On Fri, 27 Sep 2013, Orion Poplawski wrote:
> > >
> > > > On 09/27/2013 11:14 AM, David Frye wrote:
> > > > > Looks like your packet reassembly is a really hight number, and I'm
> > not sure what is causing the packets to arrive broken. The number of
> > reassembled packets is about 2.5 times the total number of incoming
> > packets, so that's a lot of extra overhead for the device.
> > > >
> > > > MTU settings?
> > > >
> > > >
> > > > --
> > > > Orion Poplawski
> > > > Technical Manager                     303-415-9701 x222
> > > > NWRA, Boulder/CoRA Office             FAX: 303-415-9702
> > > > 3380 Mitchell Lane                       orion at nwra.com
> > > > Boulder, CO 80301                   http://www.nwra.com
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